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Aim: To quantify the physiological demands and impact of muscle function t of the Fran workout, one of the most popular CrossFit benchmarks. Methods: Twenty experienced CrossFitters—16 male: 29 (6) years old and 4 female: 26 (5) years old— performed 3 rounds (with 30-s rests in between) of 21–21, 15–15, and 9–9 front squats to overhead press plus pull-up repetitions. Oxygen uptake and heart rate were measured at baseline, during the workout, and in the recovery period. Rating of perceived exertion, blood lactate, and glucose concentrations were assessed at rest, during the intervals, and in the recovery period. Muscular fatigue was also monitored at rest and at 5 minutes, 30 minutes, and 24 hours postexercise. Repeated-measures analysis of variance was performed to compare time points. Results: Aerobic (52%–29%) and anaerobic alactic (30%–23%) energy contributions decreased and the anaerobic lactic contribution increased (18%–48%) across the 3 rounds of the Fran workout. Countermovement jump height decreased by 8% (−12 to −3) mean change (95% CI), flight duration by 14% (−19 to −7), maximum velocity by 3% (−5 to −0.1), peak force 4% (−7 to −0.1), and physical performance (plank prone 47% [−54 to −38]) were observed. Conclusions: It appears that the Fran workout is a physically demanding activity that recruits energy from both aerobic and anaerobic systems. This severe-intensity workout evokes substantial postexercise fatigue and corresponding reduction in muscle function.

Purpose: To assess changes in swimming performance, anthropometrics, kinematics, energetics, and strength after 5-week training cessation. Methods: Twenty-one trained and highly trained swimmers (13 males: 17.4 [3.1] y; 50-m front crawl 463 [77] FINA points; 8 females: 16.7 [1.7] y; 50-m front crawl 535 [48] FINA points) performed a 50-m front-crawl all-out swim test, dryland and pool-based strength tests, and 10-, 15-, 20-, and 25-m front-crawl all-out efforts for anaerobic critical velocity assessment before and after a 5-week training cessation. Heart rate and oxygen uptake () were continuously measured before and after the 50-m swim test (off-kinetics). Results: Performance was impaired 1.9% (0.54 s) for males (P = .007, d = 0.91) and 2.9% (0.89 s) for females (P = .033, d = 0.93). Neither the anthropometrical changes (males: r2 = .516, P = .077; females: r2 = .096, P = .930) nor the physical activities that each participant performed during the off-season (males: r2 = .060, P = .900; females: r2 = .250, P = .734) attenuated performance impairments. Stroke rate and clean swimming speed decreased (P P > .05). Blood lactate concentrations remained similar (P > .05), but peak decreased in females (P = .04, d = 0.85). Both sexes showed higher heart rate before and after the 50-m swim test after 5 weeks (P P = .035, d = 0.65). Lower in-water force during tethered swimming at zero speed was observed in males (P = .033, d = 0.69). Regarding dryland strength, lower-body impairments were observed for males, while females showed upper-body impairments (P Conclusions: A 5-week training cessation yielded higher heart rate in the 50-m front crawl, anaerobic pathways, and dryland strength impairments. Coaches should find alternatives to minimize detraining effects during the off-season.

O Laboratório de Biomecânica do Porto (LABIOMEP-UP) é um centro de competências da Universidade do Porto dedicado ao ensino, investigação científica e tecnológica, inovação, prestação de serviços técnicos especializados e transferência de conhecimento e tecnologia em Biomecânica (humana e animal) de interesse ergonómico, clínico, desportivo ou biomimético (ex: design, animação computacional e desenvolvimento de modelos). A missão do LABIOMEP-UP é catalisar o potencial de crescimento e vantagem competitiva da Universidade do Porto em todos os domínios direta ou indiretamente relacionados com a Biomecânica, incluindo a interação com o tecido industrial e comercial.

Breath-by-breath energy expenditure during open water swimming has not yet been explored in an ecological environment. This study aimed to investigate and compare energetics and kinematics of 5 km swimming, in both swimming pool and open water conditions. Through four independent studies, oxygen uptake ( $$\dot{V}\text{O}$$ 2) kinetics, heart rate (HR), blood lactate concentration ([La−]) and glucose level (BGL), metabolic power ( $$\dot{E}$$ ), energy cost (C) and kinematics were assessed during 5 km front crawl trials in a swimming pool and open water conditions. A total of 38 competitive open water swimmers aged 16–27 years volunteered for this four part investigation: Study A (pool, ten females, 11 males), Study B (pool, four females, six males), Study C (pool case study, one female) and Study D (open water, three females, four males). In the swimming pool, swimmers started with an above average swimming speed (v), losing efficiency along the 5 km, despite apparent homeostasis for [La−], BGL, $$\dot{V}\text{O}$$ 2, $$\dot{E}$$ and C. In open water, swimmers started the 5 km with a below average v, increasing the stroke rate (SR) in the last 1000 m. In open water, $$\dot{V}\text{O}$$ 2 kinetics parameters, HR, [La−], BGL, respiratory exchange ratio and C were affected by the v and SR fluctuations along the 5 km. Small fluctuations were observed for energetic variables in both conditions, but changes in C were lower in swimming pool than in open water. Coaches should adjust the training plan accordingly to the specificity of open water swimming.

This study aimed to identify the biomechanical features of backstroke to breaststroke transition techniques (open, somersault, bucket, and crossover) in age-group swimmers. Eighteen preadolescent swimmers (12.2 ± 0.4 years old and 3–4 Tanner stages) underwent 4 weeks of systematic contextual interference training, comprising 16 sessions (40 min·session−1). Soon after, experimental testing was conducted where swimmers randomly performed 12 × 15m maximal turns (composed of 7.5m turn-in and 7.5m turn-out of the wall segments), three in each transition technique. Kinematical, kinetic, and hydrodynamic variables were assessed with a dual-media motion capture system (12 land and 11 underwater cameras), triaxial underwater force plates, and inverse dynamics. Variables were grouped in turn-in (approach and rotation) and turn-out (wall contact, gliding, and pull-out) phases, with factor analysis used to select the variables entering on multiple regressions. For the turn-in phase, 86, 77, 89, and 87% of the variance for open, somersault, bucket, and crossover turning techniques, respectively, was accounted by the 7.5 and 2.5m times, mean stroke length, and rotation time. For the turn-out phase, first gliding distance and time, second gliding depth, turn-out time, and dominating peak_Z push-off force accounted for 93% in open turn, while wall contact time, first gliding distance, breakout distance and time, turn-out time, dominating peak_Y push-off force, and second gliding drag coefficient accounted for 92% in a somersault turn. The foot plant index, push-off velocity, second gliding distance, and turn-out time accounted for 92% in bucket turn while breakout and turn-out time, non-dominating peak_Y and peak_Z push-off force, first and second gliding drag force and second gliding drag coefficient accounted for 90% in crossover turn, respectively. The findings in this study were novel and provided relevant biomechanical contribution, focusing on the key kinematic–temporal determinant during turn-in, rotation, and push-off efficacy, and the kinetic and hydrodynamic during turn-out, which would lead to improved backstroke to breaststroke transition techniques in 11–13 years-old age-group swimmers., This study was supported by the Faculty of the Sport Science, Burapha University, Thailand (grant number 062/2554). RZ was founded by Research Center in Physical Activity, Health and Leisure—CIAFEL—Faculty of Sports, University of Porto—FADEUP (FCT UID/DTP/00617/2020 and Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal (LA/P/0064/2020).

Understanding fluctuations and associations between swimming performance-related variables provide strategic insights into a swimmer's preparation program. Through network analysis, we verified the relationships between anthropometrics, maturation, and kinematics changes (Δ) in 25-m breaststroke (BREAST) and butterfly (FLY) swimming performance, before and after a 47-week swimming training season. Twenty age-group swimmers (n =11 girls: 10.0 ± 1.3 years and n = 9 boys: 10.5 ± 0.9 years) performed a 25-m all-out swim test (T25) in BREAST and FLY techniques, before and after 47 weeks. Three measures of centrality, transformed into a z-score, were generated: betweenness, closeness, and strength. Data were compared (t-test) and effect sizes were identified with Hedges' g. Large effect sizes were observed for swimming performance improvements in BREAST (32.0 ± 7.5 to 24.5 ± 3.8 s; g = 1.26; Δ = −21.9 %) and FLY (30.3 ± 7.0 to 21.8 ± 3.6 s; g = 1.52; Δ = −26.5 %). Small to moderate effect sizes were observed for anthropometric changes. Moderate effect size was observed for maturity offset changes (−2.0 ± 0.9 to −1.3 ± 1.0; g = 0.73; Δ = 50.9 ± 281 %). Changes in maturity offset, stroke rate (SR), and stroke length for both BREAST and FLY swimming speeds were highlighted by the weight matrix. For betweenness, closeness, and strength, changes in arm span (AS) (BREAST) and stroke length (FLY) were remarkable. The dynamic process of athletic development and the perception of complexity of fluctuations and associations between performance-related variables were underpinned, particularly for simultaneous swimming techniques in age-group swimmers.

Aims: analyze kinematics, anthropometrics, and maturation during a training season in 12 y and underage-group swimmers, quantifying changes and estimating their contributions to the 200-m maximal front crawl time trial test (T200) (time trial/fixed distance), as an event representative of the swimming performance. Methods: Nineteen age-group swimmers (11 girls and 8 boys; age 10.0 ± 1.3 y and 10.6 ± 1.0 y) performed a T200 four times during the training season. Changes in kinematic and anthropometric variables throughout the season were calculated. We applied generalized estimating equations to compare the variables over the four experimental tests. Multiple linear regressions were applied to identify the most influential variables and the relative contribution of anthropometrics and kinematics to swimming performance of T200 at baseline (pre-season) and after (using delta values) each macrocycle. Results: Large improvements (d = 1.76) were observed in the T200's performance (from 85.5 ± 38.2 at pre-season to 175.2 ± 50.1 FINA points at the end season). A gender effect was not identified. Stroke rate, stroke length, and stroke index explained, respectively 59, 23, and 17% of the T200 performance changes along the season (R2 = 0.81; F = 26.9; p < 0.001; Durbin-Watson: 1.5). Anthropometric was not related to performance changes, with kinematic being the most determinant factor. Conclusion: Kinematical approaches must be carefully considered by coaches when planning 12 y and underage-group swimmers training programs.

There is current scientific interest in naturally sourced phenolic compounds and their potential benefits to health, as well as the effective role polyphenols may provide in an exercise setting. This study investigated the chronic effects of supplementation with a biodynamic and organic olive fruit water phytocomplex (OliPhenolia® [OliP]), rich in hydroxytyrosol (HT), on submaximal and exhaustive exercise performance and respiratory markers of recovery. Twenty-nine recreationally active participants (42 ± 2 yrs; 71.1 ± 2.1 kg; 1.76 ± 0.02 m) consumed 2 × 28 mL∙d−1 of OliP or a taste- and appearance-matched placebo (PL) over 16 consecutive days. Participants completed a demanding, aerobic exercise protocol at ~75% maximal oxygen uptake (V˙O2max) for 65 min 24 h before sub- and maximal performance exercise tests prior to and following the 16-day consumption period. OliP reduced the time constant (τ) (p = 0.005) at the onset of exercise, running economy (p = 0.015) at lactate threshold 1 (LT1), as well as the rating of perceived exertion (p = 0.003) at lactate turnpoint (LT2). Additionally, OliP led to modest improvements in acute recovery based upon a shorter time to achieve 50% of the end of exercise V˙O2 value (p = 0.02). Whilst OliP increased time to exhaustion (+4.1 ± 1.8%), this was not significantly different to PL (p > 0.05). Phenolic compounds present in OliP, including HT and related metabolites, may provide benefits for aerobic exercise and acute recovery in recreationally active individuals. Further research is needed to determine whether dose-response or adjunct use of OliP alongside longer-term training programs can further modulate exercise-associated adaptations in recreationally active individuals, or indeed support athletic performance.

Changes in performance, energetics and kinematics during age-group swimmers off-season inform the prescription of training for the following season. Age-group swimmers (n = 15, age 14.3 ± 0.7 years) of equal maturational stage performed a 400-m front crawl (T400) before and after a four-weeks training cessation period. Performance-related energetic and kinematic variables were obtained controlling for anthropometric changes and non-swimming specific physical activities during off-season. T400 time decreased 3.8% (95%CI 1.4 to 6.1%; p 0.01

This study aimed to compare three swimming conditions in a swimming flume with water at 26 ℃ (using swimsuit) and 18 ℃ (randomly with swimsuit and wetsuit). Seventeen swimmers (32.4±14.7 years old, 175.6±0.06 cm height, and 70.4±9.8 kg body mass) performed three bouts until exhaustion at a 400-m front crawl pace (24 h intervals). ANOVA repeated measures compared the experimental conditions. Swimming at 26 ℃ with swimsuit evidenced a higher metabolic demand (total energy expenditure; (E)), comparing to 18 ℃ swimsuit (p=0.05) and with 18 ℃ wetsuit (p=0.04). The 26 ℃ swimsuit condition presented higher peak oxygen uptake (VO2peak), blood lactate concentrations ([La-]peak), rate of perceived exertion (RPE), maximal heart rate (HRmax), anaerobic lactic energy (AnL), E, energy cost (C), VO2 amplitude (Ap), and stroke rate (SR), but lower stroke length (SL) and stroke index (SI) than 18 ℃ wetsuit. The 18 ℃ swimsuit condition (comparing to wetsuit) lead to higher VO2peak, [La-]peak, HRmax, E, C, Ap, and SR but lower SL and SI. Swimming at aerobic power intensity with swim and wetsuit at 18 ℃ does not induce physiologic and biomechanical disadvantages compared to 26 ℃. The results suggested that the use of wetsuit might increase performance at 18 ℃ water temperature for competitive master swimmers. Its use is thus recommended in open water swimming competitions when the water temperature is 18–20 ℃.

Background: Physical exercise can affect the immune system. We studied the effect of antioxidants on hematological and immune biomarkers after heavy training. Methods: 24 well-trained and well-fed male firefighters were randomly divided into supplemented and placebo groups, and tested for immunology-related variables using venous blood samples in the fasting state, pre- (M1) and post- (M2) five weeks of daily micronutrient supplementation (15 mg of beta-carotene, 200 mg of vitamin C, 136 mg of vitamin E, 200 μg of selenium, 15 mg of zinc, 100 mg of magnesium). Total leukocytes and a differential count for five populations were determined using standard procedures (MAXM—Beckman Coulter Diagnostics; Brea, CA, USA). Lymphocyte subsets were determined through immunophenotyping. Results: Although all values were within the normal range for healthy adults and athletes in the supplemented group (SG), mean CD3+CD8+, CD8+ and CD16+CD56+ decreased (p < 0.05; small to moderate effects), while mean CD4+, CD19+ and CD4+/CD8+ increased (p < 0.05; small effects) after five-weeks. Regarding the placebo group (PG), higher total leukocyte count (p < 0.05; trivial effect) and natural killer cells percentage (CD16+CD56+; p < 0.05; moderate effect) were observed when comparing M1 and M2. Conclusions: Antioxidants supplementation did not alter well-fed male firefighters recruit firefighters’ immune cell response during the five-week physical training program.

Aim: The authors investigated how the Arena Powerskin R-EVO Closed Back swimsuit and Arena Carbon Triwetsuit (full-sleeve wetsuit), both approved by the Fédération Internationale de Natation (FINA) regulations, affect biomechanics and energetics of 3 elite female open water (OW) swimmers at maximal and 4 submaximal swimming intensities. Methods: Three elite female OW swimmers (OW1 = 24 y, 1.64 m, 60 kg; OW2 = 23 y, 1.69 m, 65 kg; OW3 = 27 y, 1.63 m, 64.5 kg) were tested 1 week prior to a FINA/CNSG (China National Sports Group) Marathon Swim World Series event and 40 days before the 18th FINA World Championships 2019. Each OW swimmer completed 2 identical testing sessions, one with a swimsuit and other with a wetsuit, involving shoulder flexion power output assessed from medicine-ball throw, maximal performance and drag coefficient assessment, and an incremental intermittent swim test at 4 different relative intensities. Results: Estimated peak oxygen uptake was 4.4 L·min−1 for OW1, 5.6 L·min−1 for OW2, and 5.0 L·min−1 for OW3. Despite a distinct behavior observed on index of coordination for OW3, a null index of synchronization, increased stroke rate (mean difference = 2%–8%), reduced drag factor (minimum = −14%; maximum = −30%), lower energy cost (mean difference = −2% to −6%), and faster performance (mean difference = 2% to 3%) were observed with the wetsuit compared with swimsuit for all elite OW swimmers. Conclusion: The wetsuit enhances submaximal swimming performance, and this increase is dependent on the OW swimmer’s characteristics. The higher stroke rate and lower stroke length detected with wetsuit could be related to movement constraints imposed by the suit.

Background: Range of motion (ROM) is an important feature of sports performance and health. Stretching is usually prescribed to improve promote ROM gains, but evidence has suggested that strength training (ST) also improves ROM. However, it is unclear if its efficacy is comparable to stretching. Objective: To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the effects of ST and stretching on ROM. Protocol: INPLASY: 10.37766/inplasy2020.9.0098. Data sources: Cochrane Library, EBSCO, PubMed, Scielo, Scopus, and Web of Science were consulted in early October 2020, followed by search within reference lists and consultation of four experts. No constraints on language or year. Eligibility criteria (PICOS): (P) humans of any sex, age, health or training status; (I) ST interventions; (C) stretching interventions (O) ROM; (S) supervised RCTs. Data extraction and synthesis: Independently conducted by multiple authors. Quality of evidence assessed using GRADE; risk-of-bias assessed with RoB 2. Results: Eleven articles (n = 452 participants) were included. Pooled data showed no differences between ST and stretching on ROM (ES = -022; 95% CI = -055 to 012; p = 0206). Sub-group analyses based on RoB, active vs. passive ROM, and specific movement-per-joint analyses for hip flexion and knee extension showed no between-protocol differences in ROM gains. Conclusion: ST and stretching were not different in improving ROM, regardless of the diversity of protocols and populations. Barring specific contra-indications, people who do not respond well or do not adhere to stretching protocols can change to ST programs, and vice-versa.

Objective: This study aimed at comparing different recovery-based methods to assess the highest exercise oxygen uptake value ( V ˙ O2peak) when swimming at low-moderate, heavy and severe intensities. Complementarily, the different recovery curve kinetics were analysed. Approach: Eighteen competitive swimmers performed a 5 × 200 m front crawl intermittent protocol (0.05 m · s−1 increments and 3 min intervals), with respiratory gas exchange being continuously measured breath-by-breath during and post-exercise using a portable gas analyser. The directly determined V ˙ O2peak ( V ˙ O2dir) was compared with the values obtained by linear and exponential backward extrapolations (of different intervals) and the recovery curve mathematical modelling. Main results: V ˙ O2dir rose with intensity increase: 41.96 ± 6.22, 46.36 ± 6.89 and 50.97 ± 7.28 ml · kg−1 min−1 for low-moderate, heavy and severe swims. Linear and exponential regressions applied to the first 20 s of recovery presented the V ˙ O2peak values closest to V ˙ O2dir at low-moderate (42.80 ± 5.54 vs 42.88 ± 5.58 ml kg−1 min−1), heavy (47.12 ± 4.91 vs 47.48 ± 5.09 ml kg−1 min−1) and severe intensity domains (51.24 ± 6.89 vs 53.60 ± 8.54 ml kg−1 · min−1, respectively; r = 0.5–0.8, p < 0.05). The mono-exponential function was the best fit at low-moderate and heavy intensities, while the bi-exponential function better characterized the severe exercise domain (with a slow component amplitude, time delay and time constant of 6.2 ± 2.3 ml kg−1 min−1, 116.6 ± 24.3 and 39.9 ± 15.2 s, respectively). Significance: The backward extrapolation of the first 20 s of recovery is the best method to assess the V ˙ O2peak for a large spectrum of swimming intensities. Complementarily, intensity increases imply different recovery curve kinetics, particularly a mono-exponential behaviour for low-moderate and heavy exertions and a bi-exponential dynamics for severe paces.

Surfing is one additional sport proposed by the Tokyo 2020 Organizing Committee. Surprisingly, substantial efforts to understand surfing energetics are recent, and the impact of a single surfing paddling cycle on fatigue and energy cost is still not clear. Since surfing paddling technique is highly specific, experiments in real practice conditions are necessary to provide deeper insights. Through a biophysical approach, biomechanical and energetics responses of surfing paddling were quantified and compared from 16 competitive male surfers (23.5 ± 10.0 years old, 65.3 ± 11.4 kg and 1.72 ± 0.01 m) during two sets (PRE and POST) of 10 s all-out tethered paddling plus 20 m sprint paddling, interposed by 6 min of endurance paddling. Faster surfers presented lower energy cost during sprint PRE (r2 = 0.30, p = 0.03) and endurance (r2 = 0.35, p = 0.02) relative surfing paddling velocities. Although the energy cost was higher for a lower velocity at maximal paddling velocity POST, the energy cost of surfing paddling increased with absolute velocity according to a power function (R2 = 0.83). Our results suggest that fatigue seems to occur even following a single surfing paddling cycle. Developing a powerful and endurable metabolic base while reducing energy cost during surfing paddling should be seen as key factors in surfing training programs.

Intensive physical training programs can affect the immune system. This study aims to verify the multi-micronutrient supplementation effects on serum immunoglobulins levels prior to and after a five-week physical training program. Twenty-four male recruit firefighters were randomly allocated into supplemented (with Prisfar Ever-Fit Plus over 35 consecutive days) and placebo groups (n=12 each). Serum immunoglobulins G, A, and M were assessed. Supplementation effect was detected for immunoglobulin G (eta-squared, η2: 0.09; p=0.035; power: 0.56), A (η2: 0.24; p=0.001; power: 0.95), and M (η2: 0.09; p=0.036; power: 0.56). Although immunoglobulin A was different between groups at baseline (mean difference: 42.58; 95%CI: 7.00 to 78.16 mg/dL; p=0.021; d=2.48), within-group (before vs. after five weeks) showed no differences for both supplemented and control groups. In addition, even if immunoglobulin G and M were similar at baseline, immunoglobulin G decreased (mean diff.: 46.4; 95%CI: 6.7 to 86.1 mg/dL; p=0.03; d=0.74) and immunoglobulin M increased (mean diff.: −10.7; 95%CI: −15.8 to −5.5 mg/dL; p=0.001; d=−1.33) in the control group. Although mean values remained within the reference values, changes observed for immunoglobulin G and M may reflect some immune protection for firefighters engaged in recruit training.

As discussed in the current Viewpoint (2), there have been a number of methodologically different applications of the verification phase for maximal oxygen uptake (Vo2max) over the past decade, incorporating seemingly arbitrary determination criteria. This is not to say that through observation and experiment, a more exact validation cannot be found. But rather, the immediate focus should be on developing updated protocols for accurately identifying Vo2max for various populations...

We aimed to examine the micronutrient supplementation effect on complement system activity after heavy training. 24 male firefighters were randomly divided into supplemented and placebo groups, and tested for immunology-related parameters using venous blood samples in the fasting state pre- and post-5 weeks of nutritional supplementation. C3 and C4 complement components were determined in a nephelometer from immune complexes formed through specific human antisera and total haemolytic complement activity (CH100) was determined by enzyme immunoassay. Differences between pre- and post-supplementation were observed only for CH100 on placebo group (p=0.004; mean diff −26.92; 95%CI −43.58 to −10.25) and no interaction, treatment or time effects were observed for C3 and C4. Although interaction accounted for 8.8% of the total variance in CH100 (with time effect pre- vs post-accounting for 19.5% of the total variance), the treatment effect (supplemented vs placebo) was not significant. The absence of effects on the complement system response to supplementation during heavy training could be justified by the fact that: (i) nutritional supplements do not improve humoral innate immunity in well-fed subjects; (ii) selected supplements unlikely improve the innate immune system in situations of adequate nutritional status; and/or (iii) selected doses of supplementation were not sufficient to elicit immune changes.

The anaerobic threshold (AnT) seems to be not only a physiologic boundary but also a transition after which swimmers technique changes, modifying their biomechanical behaviour. We expanded the AnT concept to a biophysical construct in the four conventional swimming techniques. Seventy-two elite swimmers performed a 5×200 m incremental protocol in their preferred swimming technique (with a 0.05 m·s−1 increase and a 30 s interval between steps). A capillary blood samples were collected from the fingertip and stroke rate (SR) and length (SL) determined for the assessment of [La], SR and SL vs. velocity inflexion points (using the interception of a pair of linear and exponential regression curves). The [La] values at the AnT were 3.3±1.0, 3.9±1.1, 2.9±1 .34 and 4.5±1.4 mmol·l−1 (mean±SD) for front crawl, backstroke, breaststroke and butterfly, and its corresponding velocity correlated highly with those at SR and SL inflection points (r=0.91–0.99, p

(1) Background: Stretching is known to improve range of motion (ROM), and evidence has suggested that strength training (ST) is effective too. However, it is unclear whether its efficacy is comparable to stretching. The goal was to systematically review and meta-analyze randomized controlled trials (RCTs) assessing the effects of ST and stretching on ROM (INPLASY 10.37766/inplasy2020.9.0098). (2) Methods: Cochrane Library, EBSCO, PubMed, Scielo, Scopus, and Web of Science were consulted in October 2020 and updated in March 2021, followed by search within reference lists and expert suggestions (no constraints on language or year). Eligibility criteria: (P) Humans of any condition; (I) ST interventions; (C) stretching (O) ROM; (S) supervised RCTs. (3) Results: Eleven articles (n = 452 participants) were included. Pooled data showed no differences between ST and stretching on ROM (ES = −0.22; 95% CI = −0.55 to 0.12; p = 0.206). Sub-group analyses based on risk of bias, active vs. passive ROM, and movement-per-joint analyses showed no between-protocol differences in ROM gains. (4) Conclusions: ST and stretching were not different in their effects on ROM, but the studies were highly heterogeneous in terms of design, protocols and populations, and so further research is warranted. However, the qualitative effects of all the studies were quite homogeneous.

To verify the metabolic responses of oxygen consumption (V[Combining Dot Above]O2), heart rate (HR), blood lactate concentrations [La], and rate of perceived exertion (RPE) when swimming at an intensity corresponding to the critical velocity (CV) assessed by a 4-parameter model (CV4par), and to check the reliability when using only a single 400-m maximal front crawl bout (T400) for CV4par assessment in age-group swimmers. Ten age-group swimmers (14-16 years old) performed 50-, 100-, 200-, 400- (T400), 800-, and 1,500-m maximal front crawl bouts to calculate CV4par. V[Combining Dot Above]O2, HR, [La], and RPE were measured immediately after bouts. Swimmers then performed 3 × 10-minute front crawl (45 seconds rest) at CV4par. V[Combining Dot Above]O2, HR, [La], and RPE were measured after 10 minutes of rest (Rest), warm-up (Pre), each 10-minute repetition, and at the end of the test (Post). CV4par was 1.33 ± 0.08 m·s. V[Combining Dot Above]O2, HR, [La], and RPE were similar between first 10-minute and Post time points in the 3 × 10-minute protocol. CV4par was equivalent to 92 ± 2% of the mean swimming speed of T400 (v400) for these swimmers. CV4par calculated through a single T400 (92%v400) showed excellent agreement (r = 0.30; 95% CI: -0.04 to 0.05 m·s, p = 0.39), low coefficient of variation (2%), and root mean square error of 0.02 ± 0.01 m·s when plotted against CV4par assessed through a 4-parameter model. These results generated the equation CV4par = 0.92 × v400. A single T400 can be used reliably to estimate the CV4par typically derived with 6 efforts in age-group swimmers.

Although performance and biomechanical evaluations are becoming more swimming-specific, dryland testing permits monitoring of a larger number of performance-related variables. However, as the degree of comparability of measurements conducted in-water and on land conditions is unclear, we aimed to assess the differences between force production in these two different conditions. Twelve elite swimmers performed a 30 s tethered swimming test and four isokinetic tests (shoulder and knee extension at 90 and 300&deg, /s) to assess peak force, peak and average torque, and power symmetry index. We observed contralateral symmetry in all the tests performed, e.g., for 30 s tethered swimming and peak torque shoulder extension at 90&deg, /s: 178 &plusmn, 50 vs. 183 &plusmn, 56 N (p = 0.38) and 95 &plusmn, 37 vs. 94 &plusmn, 35 N &times, m (p = 0.52). Moderate to very large direct relationships were evident between dryland testing and swimming force production (r = 0.62 to 0.96, p &lt, 0.05). Swimmers maintained similar symmetry index values independently of the testing conditions (r = &minus, 0.06 to &minus, 0.41 and 0.04 to 0.44, p = 0.18&ndash, 0.88). Asymmetries in water seems to be more related to technical constraints than muscular imbalances, but swimmers that displayed higher propulsive forces were the ones with greater force values on land. Thus, tethered swimming and isokinetic evaluations are useful for assessing muscular imbalances regarding propulsive force production and technical asymmetries.

This study aimed to assess the effects of post-activation potentiation in the strength related variables of a kick start. Thirteen competitive swimmers performed three kick starts after a standardized warm up (denoted USUAL) and another after inducing post-activation through five isotonic repetitions on an eccentric flywheel (denoted PAP). A T-test was used to quantify differences between USUAL and PAP warm up. The best trial of each subject achieved by natural conditions (denoted PEAK) was compared with data obtained after PAP. An instrumented starting block with independent triaxial force plates, collected the strength variables related with the impulse at take off. Improvements in the vertical components of force were observed after PAP compared with USUAL, meanwhile no differences were detected on the horizontal components of it. The velocity at take off was higher after PAP compared with the USUAL (4.32 ± 0.88 vs 3.93 ± 0.60 m*s-1; p = 0.02). No differences in force or velocity were detected comparing PAP with PEAK (4.13 ± 0.62 m*s-1, p = 0.11). The PAP warm-up increased vertical force and it was transferred to a higher resultant velocity at take-off. This improvement would equal the best result possible obtained in natural conditions after some trials., CTS-527: Actividad física y deportiva en el medio acuático

Zacca, R, Azevedo, R, Chainok, P, Vilas-Boas, JP, Castro, FAdS, Pyne, DB, and Fernandes, RJ. Monitoring age-group swimmers over a training macrocycle: energetics, technique, and anthropometrics. J Strength Cond Res 34(3): 818-827, 2020-The aim of this study was to quantify changes and contributions of energetic, technique, and anthropometric profiles across the first training macrocycle (16-week) in a traditional 3-peak swimming season. Twenty-four age-group swimmers (10 boys and 14 girls age 14.4 ± 0.9 years) of equal maturational stage were monitored through a 400-m test in front crawl (T400). Energetic, technique, and anthropometric characteristics were compared before (experimental testing 1, E1) and after the preparatory (E2), specific (E3), and competitive (E4) training periods. Sex interaction was not significant for any variable. Multiple linear regressions and principal component analysis were used to identify the most influential variables and the relative contribution of each domain (energetics, technique, and anthropometrics) to changes in swimming performance of T400. The relative contributions for performance of T400 at E1, E2, E3, and E4 were 15, 12, 6, and 13% for energetics, 78, 85, 75, and 70% for technique, and 7, 3, 19 and 17% for anthropometrics, respectively. Technique played the main role during the first 16-week macrocycle in a competitive season, regardless of small fluctuations in the influence of energetics and anthropometrics. Changes and influence of energetics, technique, and anthropometric on age-group swimmers' performance could be described by the T400 swimming test, providing a comprehensive biophysical overview of the main contributors to swimming performance.

Zacca, R, Azevedo, R, Peterson Silveira, R, Vilas-Boas, JP, Pyne, DB, Castro, FAdS, and Fernandes, RJ. Comparison of incremental intermittent and time trial testing in age-group swimmers. J Strength Cond Res 33(3): 801-810, 2019-The aim of this study was to compare physiological and biomechanical characteristics between an incremental intermittent test and a time trial protocol in age-group swimmers. Eleven national level age-group swimmers (6 men and 5 women) performed a 7 × 200-m incremental intermittent protocol (until exhaustion; 30-second rest) and a 400-m test (T400) in front crawl on separate days. Cardiorespiratory variables were measured continuously using a telemetric portable gas analyzer. Swimming speed, stroke rate, stroke length, and stroke index were assessed by video analysis. Physiological (oxygen uptake, heart rate, and lactate concentrations) and biomechanical variables between seventh 200-m step (in which the minimal swimming speed that elicits maximal oxygen uptake-vV[Combining Dot Above]O2max was identified) and T400 (time trial/fixed distance) were compared with a paired student's t test, Pearson's product-moment correlation, Passing-Bablok regression, and Bland-Altman plot analyses. There were high level of agreement and high correlations (r-values ∼0.90; p ≤ 0.05) for all physiological variables between the seventh 200-m step and T400. Similarly, there were high level of agreements and high correlations (r-values ∼0.90; p ≤ 0.05) for all biomechanical variables and only trivial bias in swimming speed (0.03 m·s; 2%). Primary physiological and biomechanical responses between incremental intermittent and representative time trial protocols were similar, but best practice dictates protocols should not be used interchangeably to minimize errors in prescribing swimming training speeds. The T400 is a valid, useful, and easier to administer test for aerobic power assessment in age-group swimmers.

Purpose: to compare different methods to assess the arm stroke efficiency (?F ), whenswimming front crawl using the arms only on the Measurement of Active Drag System (MADSystem) and in a free-swimming condition, and to identify biophysical adaptations to swimming onthe MAD System and the main biophysical predictors of maximal swimming speed in the 200 mfront crawl using the arms only (?200m). Methods: fourteen swimmers performed twice a 5 &times, 200 mincremental trial swimming the front crawl stroke using the arms only, once swimming freely, andonce swimming on the MAD System. The total metabolic power was assessed in both conditions.The biomechanical parameters were obtained from video analysis and force data recorded on theMAD System. The ?F was calculated using: (i) direct measures of mechanical and metabolic power(power-based method), (ii) forward speed/hand speed ratio (speed-based method), and (iii) thesimplified paddle-wheel model. Results: both methods to assess ?F on the MAD System differed (p&lt, 0.001) from the expected values for this condition (?F = 1), with the speed-based method providingthe closest values (?F~0.96). In the free-swimming condition, the power-based (?F~0.75), speedbased(?F~0.62), and paddle-wheel (?F~0.39) efficiencies were significantly different (p &lt, 0.001).Although all methods provided values within the limits of agreement, the speed-based methodprovided the closest values to the &ldquo, actual efficiency&rdquo, The main biophysical predictors of ?200mwere included in two models: biomechanical (R2 = 0.98) and physiological (R2 = 0.98). Conclusions:our results suggest that the speed-based method provides the closest values to the &ldquo, actual ?F&rdquo, andconfirm that swimming performance depends on the balance of biomechanical and bioenergeticparameters

O objetivo deste artigo foi efetuar uma revisão da origem do conceito e da aplicação da velocidade crítica (VC) na natação. Em relação ao significado fisiológico, aumentos substanciais de alguns marcadores fisiológicos (concentração de lactato, consumo de oxigênio e frequência cardíaca) foram observados durante esforços em intensidade retangular à VC, sugerindo que esta se situe acima do limiar anaeróbio e também da máxima fase estável de lactato. É sugerido que a VC seja influenciada por alguns fatores como: (1) utilização de diferentes combinações de distâncias para a sua determinação; (2) diferentes faixas etárias e (3) nível de experiência do nadador. Pode-se concluir que a VC é um adequado parâmetro para o controle dos efeitos do treinamento, e pode ser obtida de maneira simples em relação a outras formas de controle. No entanto, sua utilização como ferramenta para a predição do desempenho em natação ainda necessita ser melhor investigada.The aim of this paper was to review the origin of the critical speed (CS) concept and how it may be applied to swimming. Regarding the physiological significance, substantial increases in some physiological markers (blood lactate, oxygen consumption and heart rate) were observed in rectangular intensity efforts during the CS, suggesting that this is above the anaerobic threshold and the maximal steady state lactate. Factors influencing CS are thought to include (1) using different combinations of distances used in the test to determine CS, (2) age of the individual, and (3) the swimmer's level of experience. It can be concluded that the CS represents an adequate tool for controlling training intensity and has the benefit of being comparatively simple to measure in relation to others forms of control. However, use of CS as a tool for predicting performance in swimming still needs further investigation.

Critical velocity (CV), anaerobic distance capacity (ADC), maximal instantaneous velocity (V (max)), and aerobic inertia (tau) were calculated from two (CV(2par) and ADC(2par)), three (CV(3par), ADC(3par), and V (max 3par)), and four-parameter model data (CV(4par), ADC(4par), V (max 4par), and tau), which were obtained from six different times and distances (50, 100, 200, 400, 800, and 1,500 m) swum in front crawl stroke under maximal intensity. Fourteen swimmers (14-15-year-old; sprint and endurance groups, each group n = 7) volunteered in this study. CV values were not influenced by the groups. The model effects showed that CV(2par) was higher than CV(3par) and CV(4par) regardless of the group used. In addition, CV(3par) and CV(4par) were similar. ADC seems to be better estimated using both three- and four-parameter models. V (max) was higher in the sprint group regardless of the model used. The models effects showed that the V (max 4par) was higher than the V (max 3par) regardless of the group. Sprint and endurance groups showed similar tau values. The analysis of the models (F test, coefficient of determination R (2), and adjusted coefficient of determination R (adjusted) (2) ) showed that the three-parameter model was more appropriate among the applied models. Although the four-parameter model showed better correlation for the endurance group, the inclusion of tau (fourth parameter) did not significantly improve the quality of adjustment. However, it is important to emphasize the availability of another parameter for the study of bioenergetics in swimming and other sports.

Velocidade Crí­tica (VC): máxima intensidade sustentável por um perí­odo prolongado sem alcançar o VO2máx, ou seja, o limite inferior da zona de intensidades severas. Objetivo: obter e comparar valores de VC obtidos por meio de nove modelos de diferentes números e combinações de distâncias, utilizando o mesmo grupo de nadadores. Método: Onze nadadores juvenis (idade: 14,4 ± 0,5 anos, massa corporal: 60,6 ± 7,0 kg, estatura: 175,5 ± 5,2 cm, envergadura: 182,2 ± 4,9 cm), com í­ndice de participação em Campeonatos Brasileiros participaram deste estudo. Para a determinação dos diferentes modelos de VC, os atletas realizaram, em nado crawl, testes de 50 m, 100 m, 200 m, 400 m, 800 m e 1500 m sob máxima intensidade. Para a determinação da VC1 foram utilizadas as distâncias de 50 e 200 m; VC2, 100 e 400 m; VC3, 200 e 800 m, VC4, 400 e 1500 m, VC5, 50, 100 e 200 m; VC6, 100, 200 e 400 m; VC7, 200, 400 e 800 m; VC8, 400, 800 e 1500 m; e para a VC9, 50, 100, 200 e 400 m. Resultados: VC1 (1,28 ± 0,07 m/s), VC5 (1,27 ± 0,07 m/s) e VC9 (1,26 ± 0,07 m/s) apresentaram maiores valores que VC4 (1,19 ± 0,09 m/s) e VC8 (1,19 ± 0,10 m/s). VC4 e VC8 foram semelhantes aos modelos VC2 (1,25 ± 0,07 m/s), VC3 (1,21 ± 0,07 m/s), VC6 (1,25 ± 0,07 m/s) e VC7 (1,20 ± 0,07 m/s). VC6 foi similar a todos os modelos de VC. Conclusão: distâncias percorridas em aproximadamente 60 segundos ou menos parecem induzir a valores mais altos de VC comparados a outras combinações, sugerindo assim a exclusão da distância de50 m e, se necessário, também a distância de100 m na confecção de modelos para determinação da mesma. Por outro lado, a exclusão das distâncias mais longas (800 m e1500 m) parece não alterar o valor da VC em relação aos modelos de VC confeccionados com inclusão de distâncias percorridas em tempos superiores a 60 s.Palavras-chave: natação, desempenho, potência crí­tica.Â

Systematic assessments of athletes’ physiological conditions are central to monitor and prescribe swimming training according to the needs and goals. Thus, it is possible to understand the current physiological state and follow its development in order to assess the effects of training, to identify the swimmer's skills profile and to predict athletic performance (Vilas-Boas & Lamares 1997). Specifically regarding swimmers and their skills, aerobic capacity is a major determinant of these athletes performance, and it is defined as the ability to maintain a high percentage of maximal oxygen uptake (VO2max) for a long period of time (DI PRAMPERO et al., 2011). Furthermore, the endurance is influenced by VO2max, swimming economy (or energy cost, defined as the total energy expenditure required to move the body to a certain distance in a determined velocity) and anaerobic capacity (Dekerle & Pelayo 2011). In a group of swimmers with similar values of swimming economy and anaerobic capacity, those with greater aerobic potential (VO2max and aerobic capacity) will be faster at distances of 400 m and longer. Four hundred meters, when swimming in front crawl, is usually suggested as a trial in which VO2max is reached (Dekerle & Pelayo 2011). Thus, the longer events (800 m, 1500 m and open water marathon), which are covered primarily with energy from aerobic metabolism, are covered in a fraction of the VO2max. The intensity will be lower the longer is the distance, reaching 60-65% of VO2max on the 25 km open water marathon (Zamparo et al. 2005). In this sense, one of the objectives of the swimming training is to increase the aerobic capacity. Thus, a valid and reliable measure of the swimmer aerobic profile is essential to verify the benefits that the training program is or is not providing, and, also, to set training intensities according to the physiological profile of the athlete. Dekerle & Pelayo (2011) emphasize that the methodology used for this purpose cannot be considered valid unless it is reliable. Whenever possible, the degree of reliability should be assessed. The origin of the variability measurement (human error, equipment error, biological variation, or motivational factors when performing the test) needs to be taken into account. Thus, the aim of this chapter is to present a careful review of the bioenergetics contribution on the physiological assessment of the swimmer, especially related to aerobic profile.

O objetivo deste artigo foi efetuar uma revisão da origem do conceito e da aplicação da velocidade crítica (VC) na natação. Em relação ao significado fisiológico, aumentos substanciais de alguns marcadores fisiológicos (concentração de lactato, consumo de oxigênio e frequência cardíaca) foram observados durante esforços em intensidade retangular à VC, sugerindo que esta se situe acima do limiar anaeróbio e também da máxima fase estável de lactato. É sugerido que a VC seja influenciada por alguns fatores como: (1) utilização de diferentes combinações de distâncias para a sua determinação; (2) diferentes faixas etárias e (3) nível de experiência do nadador. Pode-se concluir que a VC é um adequado parâmetro para o controle dos efeitos do treinamento, e pode ser obtida de maneira simples em relação a outras formas de controle. No entanto, sua utilização como ferramenta para a predição do desempenho em natação ainda necessita ser melhor investigada. The aim of this paper was to review the origin of the critical speed (CS) concept and how it may be applied to swimming. Regarding the physiological significance, substantial increases in some physiological markers (blood lactate, oxygen consumption and heart rate) were observed in rectangular intensity efforts during the CS, suggesting that this is above the anaerobic threshold and the maximal steady state lactate. Factors influencing CS are thought to include (1) using different combinations of distances used in the test to determine CS, (2) age of the individual, and (3) the swimmer's level of experience. It can be concluded that the CS represents an adequate tool for controlling training intensity and has the benefit of being comparatively simple to measure in relation to others forms of control. However, use of CS as a tool for predicting performance in swimming still needs further investigation.

The assessment of oxygen uptake (VO2) kinetics is a valuable non-invasive way to evaluate cardiorespiratory and metabolic response to exercise. The aim of the study was to develop, describe and evaluate an online VO2 fitting tool (VO2FITTING) for dynamically editing, processing, filtering and modelling VO2 responses to exercise. VO2FITTING was developed in Shiny, a web application framework for R language. Validation VO2 datasets with both noisy and non-noisy data were developed and applied to widely-used models (n = 7) for describing different intensity transitions to verify concurrent validity. Subsequently, we then conducted an experiment with age-group swimmers as an example, illustrating how VO2FITTING can be used to model VO2 kinetics. Perfect fits were observed, and parameter estimates perfectly matched the known inputted values for all available models (standard error = 0, p &lt, 0.001). The VO2FITTING is a valid, free and open-source software for characterizing VO2 kinetics in exercise, which was developed to help the research and performance analysis communities.

Understanding more about competitive swimmers and their athletic potential requires organized, systematic and consistent evaluation. The evaluation and training control of swimmers give the coach valuable information about an athlete's improvement, stagnation, or deterioration in training and competitive performance. Assessments addressing both biological and physical aspects are usually called biophysical studies. This type of integrated approach allows a deeper understanding of the determinant variables in swimming and how they combine to enhance performance. However, few biophysical studies have been conducted on age-group swimmers, and almost all of them have been crosssectional rather than longitudinal in design. Although cross-sectional analysis is relevant, it is not sufficient to fully describe time-course and factors influencing progression over a training period. The aim of this Thesis was to quantify change in and relationships between energetics, technique and anthropometrics characteristics in age-group swimmers during a training traditional periodization design. For that aim, we developed and validated methodological tools and protocols. Useful tools have been developed for the sports/research community, highlighting the importance of a biophysical approach to evaluate swimming performance through longitudinal studies. We validated the 400-m test (T400) against the gold standard 7 x 200-m incremental intermittent protocol, comparing physiological and biomechanical characteristics in national level age-group swimmers. We also paved the way towards a straightforward analysis of oxygen uptake (V̇ O2) kinetics in exercise by developing a freely available and open-source software, which eases the V̇ O2 kinetics analysis in exercise, and can be applied for research and performance diagnostics in elite, sub-elite or recreational athletes. We then performed three longitudinal experiments. In the first longitudinal study, physiological and biomechanical effects of a typical off-season period were quantified in age-group swimmers, controlling growth and non-swimming specific physical activities performed during this training cessation period. In the second study, we quantified changes and contributions of energetic, technique and anthropometric profiles across the first training macrocycle (16-week) in a traditional three-peak swimming season. Finaly, we identified changes in energetics, technique and anthropometric profile while following age-group swimmers over a training season trough a traditional three-peak preparation program. We are confident that these methodological and longitudinal studies provide relevant tools and cientific contribution to the sports and scientific community, helping to better understand the relationships between performance-related domains.